<?php
class db extends PDO
{
    private $error;
    private $sql;
    private $bind;
    private $errorCallbackFunction;
    private $errorMsgFormat;

    public function __construct($dsn, $user="", $passwd="")
    {
        $options = array(
                       PDO::ATTR_PERSISTENT => true,
                       PDO::ATTR_ERRMODE => PDO::ERRMODE_EXCEPTION
                   );

        try
        {
            parent::__construct($dsn, $user, $passwd, $options);
        }
        catch (PDOException $e)
        {
            $this->error = $e->getMessage();
        }
    }

    private function debug()
    {
        if(!empty($this->errorCallbackFunction))
        {
            $error = array("Error" => $this->error);
            if(!empty($this->sql))
                $error["SQL Statement"] = $this->sql;
            if(!empty($this->bind))
                $error["Bind Parameters"] = trim(print_r($this->bind, true));

            //########## Someworkaround for known PHP bug######//
            $aTrace = debug_backtrace();
            // Loop backwards (!) through array
            for ( $sFile = '', $iLine = 0, $i = count( $aTrace ); $i--; )
            {
                // Make sure all fields are set
                $aTrace[$i] = array_merge(
                                  array(
                                      'function' => '',
                                      'type' => '',
                                      'class' => '',
                                      'object' => array(),
                                      'args' => array(),
                                      'file' => $sFile,
                                      'line' => $iLine),
                                  $aTrace[$i]
                              );

                // Add this for convenience
                $aTrace[$i]['call'] = $aTrace[$i]['class'] . $aTrace[$i]['type'] . $aTrace[$i]['function'];

                // Missing file or line? Copy from previous item
                $sFile = $aTrace[$i]['file'];
                $iLine = $aTrace[$i]['line'];
            }

            // Remove first item ("this function")
            array_shift( $aTrace );
            if(!empty($aTrace))
            {
                foreach($aTrace as $info)
                {
                    if($info["file"] != __FILE__)
                        $error["Backtrace"] = $info["file"] . " at line " . $info["line"];
                }
            }

            $msg = "";
            if($this->errorMsgFormat == "html")
            {
                if(!empty($error["Bind Parameters"]))
                    $error["Bind Parameters"] = "<pre>" . $error["Bind Parameters"] . "</pre>";
                $css = trim(file_get_contents(dirname(__FILE__) . "/error.css"));
                $msg .= '<style type="text/css">' . "\n" . $css . "\n</style>";
                $msg .= "\n" . '<div class="db-error">' . "\n\t<h3>SQL Error</h3>";
                foreach($error as $key => $val)
                $msg .= "\n\t<label>" . $key . ":</label>" . $val;
                $msg .= "\n\t</div>\n</div>";
            }
            elseif($this->errorMsgFormat == "text")
            {
                $msg .= "SQL Error\n" . str_repeat("-", 50);
                foreach($error as $key => $val)
                $msg .= "\n\n$key:\n$val";
            }

            $func = $this->errorCallbackFunction;
            $func($msg);
        }
    }

    public function delete($table, $where, $bind="")
    {
        $sql = "DELETE FROM " . $table . " WHERE " . $where . ";";
        return $this->run($sql, $bind);
    }

    private function filter($table, $info)
    {
        $driver = $this->getAttribute(PDO::ATTR_DRIVER_NAME);
        if($driver == 'sqlite')
        {
            $sql = "PRAGMA table_info('" . $table . "');";
            $key = "name";
        }
        elseif($driver == 'mysql')
        {
            $sql = "DESCRIBE " . $table . ";";
            $key = "Field";
        }
        else
        {
            $sql = "SELECT column_name FROM information_schema.columns WHERE table_name = '" . $table . "';";
            $key = "column_name";
        }

        if(false !== ($list = $this->run($sql)))
        {
            $fields = array();
            foreach($list as $record)
            $fields[] = $record[$key];
            return array_values(array_intersect($fields, array_keys($info)));
        }
        return array();
    }

    private function cleanup($bind)
    {
        if(!is_array($bind))
        {
            if(!empty($bind))
                $bind = array($bind);
            else
                $bind = array();
        }
        return $bind;
    }

    public function insert($table, $info)
    {
        $fields = $this->filter($table, $info);
        $sql = "INSERT INTO " . $table . " (" . implode($fields, ", ") . ") VALUES (:" . implode($fields, ", :") . ");";
        $bind = array();
        foreach($fields as $field)
        $bind[":$field"] = $info[$field];
        return $this->run($sql, $bind);
    }

    public function run($sql, $bind="")
    {
        $this->sql = trim($sql);
        $this->bind = $this->cleanup($bind);
        $this->error = "";

        try
        {
            $pdostmt = $this->prepare($this->sql);
            if($pdostmt->execute($this->bind) !== false)
            {
                if(preg_match("/^(" . implode("|", array("select", "describe", "pragma")) . ") /i", $this->sql))
                    return $pdostmt->fetchAll(PDO::FETCH_ASSOC);
                elseif(preg_match("/^(" . implode("|", array("delete", "insert", "update")) . ") /i", $this->sql))
                return $pdostmt->rowCount();
            }
        }
        catch (PDOException $e)
        {
            $this->error = $e->getMessage();
            $this->debug();
            return false;
        }
    }

    public function select($table, $where="", $bind="", $fields="*")
    {
        $sql = "SELECT " . $fields . " FROM " . $table;
        if(!empty($where))
            $sql .= " WHERE " . $where;
        $sql .= ";";
        return $this->run($sql, $bind);
    }

    public function setErrorCallbackFunction($errorCallbackFunction, $errorMsgFormat="html")
    {
        //Variable functions for won't work with language constructs such as echo and print, so these are replaced with print_r.
        if(in_array(strtolower($errorCallbackFunction), array("echo", "print")))
            $errorCallbackFunction = "print_r";

        if(function_exists($errorCallbackFunction))
        {
            $this->errorCallbackFunction = $errorCallbackFunction;
            if(!in_array(strtolower($errorMsgFormat), array("html", "text")))
                $errorMsgFormat = "html";
            $this->errorMsgFormat = $errorMsgFormat;
        }
    }

    public function update($table, $info, $where, $bind="")
    {
        $fields = $this->filter($table, $info);
        $fieldSize = sizeof($fields);

        $sql = "UPDATE " . $table . " SET ";
        for($f = 0; $f < $fieldSize; ++$f)
        {
            if($f > 0)
                $sql .= ", ";
            $sql .= $fields[$f] . " = :update_" . $fields[$f];
        }
        $sql .= " WHERE " . $where . ";";

        $bind = $this->cleanup($bind);
        foreach($fields as $field)
        $bind[":update_$field"] = $info[$field];

        return $this->run($sql, $bind);
    }
}
?>
